From: Narbik Kocharians (narbikk@gmail.com)
Date: Sun Oct 19 2008 - 07:33:36 ARST
I hope this will help: i put together some tasks to help some of you see the
difference between the optional keywords. Please excuse the typos.... if
any....
Let's say R1 is directly connected to R2 via F0/0 interface; try this lab
and you will NEVER forget what they do.
*Lab Setup:*
X Configure the F0/0 interface of both routers (R1 and R2) in VLAN 100
X Use the IP addressing chart for IP address assignment
* *
*IP addressing:*
*Router*
*Interface / IP address*
R1
F0/0 = 10.1.1.1 /24
Loopback0 = 1.1.1.1 /8
R2
F0/0 = 10.1.1.2 /24
F0/1 = 10.2.2.2 /24
Loopback0 = 2.2.2.2 /8
* *
*Task 1*
Configure R1 in AS 100 to establish an EBGP session with R2 in AS 200.
*On R1*
R1(config)#router bgp 100
R1(config-router)#no auto-summary
R1(config-router)#network 1.0.0.0
R1(config-router)#neighbor 10.1.1.2 remote-as 200
*On R2*
R2(config)#router bgp 200
R2(config-router)#no auto-summary
R2(config-router)#network 2.0.0.0
R2(config-router)#neighbor 10.1.1.1 remote-as 100
*To verify the configuration:*
* *
*On R1*
* *
*R1#Show ip bgp | b Network*
Network Next Hop Metric LocPrf Weight Path
*> 1.0.0.0 0.0.0.0 0 32768
i
*> 2.0.0.0 10.1.1.2 0
0 *200* i
*On R2*
*R2#Show ip bgp | b Network*
Network Next Hop Metric LocPrf Weight Path
*> 1.0.0.0 10.1.1.1 0
0 *100* i
*> 2.0.0.0 0.0.0.0 0 32768
i
*Note from R2's perspective prefix 1.0.0.0/8 was originated & advertised by
AS 100, and from R1's perspective, prefix 2.0.0.0/8 was originated and
advertised by AS 200.*
*Task 2*
Configure R1 in AS 111 to establish an EBGP session with R2 in AS 200 such
that the output of the "Show ip bgp" command on these two routers will be
identical to the follows:
*On R1*
* *
*R1#Sh ip bgp*
* *
BGP table version is 3, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 1.0.0.0 0.0.0.0 0 32768
i
**> 2.0.0.0 10.1.1.2 0
0 100 200 i*
*On R2*
*R2#Show ip bgp*
* *
BGP table version is 5, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale
Network Next Hop Metric LocPrf Weight Path
**> 1.0.0.0 10.1.1.1 0
0 100 111 i*
*> 2.0.0.0 0.0.0.0 0
32768 i
*On R1*
R1(config)#router bgp 111
R1(config-router)#no auto-summary
R1(config-router)#network 1.0.0.0
R1(config-router)#neighbor 10.1.1.2 remote-as 200
R1(config-router)#neighbor 10.1.1.2 local-as 100
*By changing the AS number of R1 to 111, and a "Neighbor 10.1.1.2 local-as
100" R2 will see R1's real AS of 111 originating the route and then AS 100
was the AS that advertised it. Note on R1, it shows that prefix
2.0.0.0/8was originated by AS 200 but the advertising AS to R1 was AS
100. They both
see this invisible AS 100.*
*Task 3*
Configure R1 such that when R2 advertises network 2.0.0.0/8, the output of
the "Show ip bgp" command on R1 is identical to the following:
*On R1*
*R1#Sh ip bgp*
* *
BGP table version is 5, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 1.0.0.0 0.0.0.0 0 32768
i
*> 2.0.0.0 10.1.1.2 0
0 200 i
* *
*On R1*
R1(config)#router bgp 111
R1(config-router)#neighbor 10.1.1.2 local-as 100 *no-prepend*
* *
*The "no-prepend" option tells R2 NOT to prepend AS 100 to the advertised
prefixes. This will ONLY affect R1's BGP table.*
* *
*On R1*
* *
*R1#Show ip bgp*
BGP table version is 5, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 1.0.0.0 0.0.0.0 0 32768
i
*> 2.0.0.0 10.1.1.2 0
0 200 i
*On R2*
*R2#Show ip bgp*
BGP table version is 7, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 1.0.0.0 10.1.1.1 0
0 100 111 i
*> 2.0.0.0 0.0.0.0 0
32768 i
*
*
*Task 4*
Configure R1 such that the output of the "Show ip bgp" command on R2 is
identical to the following:
**
*On R2*
* *
*R2#Show ip bgp | b Network*
* *
Network Next Hop Metric LocPrf Weight Path
*> 1.0.0.0 10.1.1.1 0
0 100 i
*> 2.0.0.0 0.0.0.0 0 32768
i
*On R1*
R1(config)#router bgp 111
R1(config-router)#neighbor 10.1.1.2 local-as 100 no-prepend replace-as
* *
*Note the "replace-as" option tells the router NOT to prepend the real AS
number.*
* *
*On R2*
* *
*R2#Show ip bgp | b Network*
* *
Network Next Hop Metric LocPrf Weight Path
*> 1.0.0.0 10.1.1.1 0
0 100 i
*> 2.0.0.0 0.0.0.0 0 32768
i
*Task 5*
Configure R1 such that R2 can establish an EBGP peer session with R1 using
AS 111 or 100.
*On R1*
R1(config)#router bgp 111
R1(config-router)#neighbor 10.1.1.2 local-as 100 no-prepend replace-as *
dual-as*
*On R1*
* *
*R1#Show ip bgp*
BGP table version is 5, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 1.0.0.0 0.0.0.0 0 32768
i
*> 2.0.0.0 10.1.1.2 0
0 200 i
* *
*On R2*
* *
*R2#Show ip bgp*
BGP table version is 13, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
**> 1.0.0.0 10.1.1.1 0
0 100 i*
*> 2.0.0.0 0.0.0.0 0 32768
i
*The current configuration of R2 is as follows:*
* *
*On R2*
* *
*R2#Show run | b router bgp 200*
router bgp 200
no synchronization
bgp log-neighbor-changes
network 2.0.0.0
neighbor 10.1.1.1 remote-as 100
no auto-summary
*Note its establishing a peer session with R1 using AS 100, the following
verifies that R2 can also establish a peer session with R1 using AS 111:*
*On R2*
R2(config)#router bgp 200
R2(config-router)#no auto-summary
R2(config-router)#netw 2.0.0.0
R2(config-router)#neighbor 10.1.1.1 remote-as 111
*To verify the configuration:*
* *
*On R2*
* *
*R2#Show ip bgp*
BGP table version is 3, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
**> 1.0.0.0 10.1.1.1 0
0 111 i*
*> 2.0.0.0 0.0.0.0 0 32768
i
On Sat, Oct 18, 2008 at 9:27 AM, But Nicky <lyredhair@gmail.com> wrote:
> Example: task 5.1 IE Workbook Vol 2 Lab 19 is a detail example.
> Regards,
> But Nguyen,
>
>
> Blogs and organic groups at http://www.ccie.net
>
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-- Narbik Kocharians CCSI#30832, CCIE# 12410 (R&S, SP, Security) www.MicronicsTraining www.Net-Workbooks.com Sr. Technical InstructorBlogs and organic groups at http://www.ccie.net
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